This invention relates generally to therapeutic mattress systems, and more particularly, to inflatable cellular mattress systems that use dynamic pressure control systems.
Individuals who are confined to wheelchairs and/or who are confined to a bed may run the risk of tissue breakdown and the development of pressure sores, which are extremely dangerous and difficult to cure. More specifically, as such individuals are primarily in a seated position for extended periods of time, their weight may be concentrated in the bonier portions of the individual's buttocks, for example. Over time, blood flow to such areas may decrease, causing tissue to break down in these areas. The problems may be further exacerbated when individuals are confined to a bed or are required to remain in a prone position for an extended period of time.
To facilitate reducing the weight concentration of such individuals, at least some users seated in at least some known wheelchairs and/or confined to a bed, use cellular structures to facilitate distributing the individual's weight over a larger area, and to facilitate decreasing their weight concentration in smaller areas. More specifically, in at least some known cellular structures, because the plurality of air-filled cells are coupled in flow communication through the base, the internal pressure exerted by the air within such cells is at the same pressure throughout the plurality of cells, and as such, each cell exerts the same pressure against the portion of the individual in contact with the structure. To increase the stability and comfort level of the user, at least some known cellular structures are divided into isolated zones of cells, wherein the cells of each zone are only coupled in flow communication with the cells within their zone. By varying the pressure between the isolated zones, the user may be able to increase their stability on the cellular cushion depending on the physical condition of the user. For example, U.S. Patent Application 2007/00707684 describes an inflatable cellular mattress in which the mattress cells are divided into two large zones of cells. Each zone of cells includes an inlet valve and an exhaust valve that enables the pressure in each zone of cells to be altered independently of the pressure in the cells in the adjoining zone. Dividing the cells into two zones enables a concentrated pressure to be selectively induced to the patient. Specifically, and as described in U.S. Pending Patent Application 2007/00707684, for example, alternating the pressure in the two zones of cells induces percussive forces to the patient that are roughly equivalent to the force a nurse would induce to a patient to break loose phlegm from the walls of the lungs by beating on the patient's back in the lung area. Moreover, within mattresses such as this, if any cell in either zone develops a leak, air may leak from all of the cells within that zone.